What's Wrong With Rosie?
Trevor Rosenthal has been off and on this year. I believe that part of the problem is that he has been throwing a cutter.[1]
At the start of the year, starting with Opening Day, I thought this was on purpose; that Rosenthal was playing around with the pitch in an effort to develop a starter's repertoire. However, I have come to believe that this is more likely an accident, perhaps due to Rosenthal's over-throwing the ball of late.[2]
I clearly saw this problem pop up again in the game yesterday 8/17 when Rosenthal walked three batters. I happened to be shooting video from center field and shot a clip containing the frame above. This frame shows the release point and shows Rosenthal's hand, rather than coming straight through the back of the ball, instead sliding around to the third base side of the ball.
This is exactly what you want to do if you want to cut the ball and get it to move to the glove side (as with a cutter or slider).
However, this is a problem if you don't mean to do this.
This was the last pitch that Rosenthal threw yesterday and, judging by Cruz's reaction, he wasn't expecting the pitch to move in that direction or that much. Presumably, Rosenthal wasn't either. Regardless, the ball moved so much more than Cruz expected that he essentially reverse-framed the pitch and turned a strike on the black into a ball.
[1] In most cases, the cutter comes in at 96MPH and moves to Rosenthal's glove side rather than flat or to his pitching arm side.
[2] When Rosenthal is on, through my camera lens a 98+MPH fastball looks like a change-up, leaving me surprised when I see the velocity reading of the pitch. Lately, I have found that I am less and less confused by what Rosenthal is throwing.